The present invention relates to an applicator beam used in a size press which comprises a nip formed by a pair of press rolls. A paper web or board is passed through the nip. A first press roll in the size press is mounted by means of bearings permanently on the frame of the size press. The second press roll is mounted on the frame of the size press by means of its bearings in a manner such that it is displaceable by means of loading arms or equivalent.
The press rolls in the size press are provided with coating devices for spreading films of a coating agent onto the faces of the rolls. The coating devices are mounted on applicator beams which are placed in the transverse direction of the machine, i.e. the size press. The applicator beams are linked pivotally on the frame of the size press or on the loading arms of the displaceable roll by means of a pivot shaft arranged transverse to the machine direction. Further, the applicator beams are provided with pivot cylinders, by whose means the applicator beams can be pivoted between a closed position, i.e. the operating position, and an open position, i.e. the service position.
The construction of a prior art size press is illustrated in FIG. A1. In FIG. A1, the size press is denoted generally with reference numeral 100. Press rolls 112, 114 in the size press 100 form a nip N with each other through which a paper or board web W is passed to be coated with a coating agent such as size. The web W is guided into the nip N over a guide roll 119. A bearing 113 of the first press roll 112 is permanently mounted, or fixed, on a frame 111 of the size press. A bearing 115 of the second press roll 114 is mounted on a loading arm 116. The loading arm 116 is arranged to pivot by means of an articulated joint 118 arranged on the frame 111 of the size press. Loading cylinders 117 are arranged between the frame 111 and the loading arm 116. The loading cylinders 117 function so that the nip N can be opened and closed and also so that the loading pressure between the rolls 112, 114, i.e. the nip pressure, can be adjusted to a desired level.
Each of the press rolls 112, 114 in the size press 100 is provided with an accompanying coating device 123, 123a, respectively. The coating devices 123, 123a apply a film of a coating agent onto the face of the respective roll 112, 114. The film is transferred onto the web W in the roll nip N. The coating devices 123, 123a are separately mounted on an applicator beam 120, 120a, respectively, arranged transverse to the machine direction. In the prior art device shown in FIG. A1, the applicator beam 120a of the first press roll 112 is mounted pivotally by means of articulated joint 121a on the frame 111 of the size press. Pivot cylinders 122a are arranged between the applicator beam 120a and the frame 111 of the size press. The pivot cylinders 122a function to open and close the applicator beam 120a in relation to the roll 112.
In a corresponding manner, the coating device 123 of the second press roll 114 is mounted on an applicator beam 120 arranged transverse to the machine direction. Applicator beam is mounted on the loading arm 116 pivotally by means of the articulated joint 121. Pivot cylinders 122 are arranged between the applicator beam 120 and the loading arm 116. By means of the pivot cylinders 122, the applicator beam 120 can be opened and closed in relation to the second press roll 114.
In the prior art size press 100 described above, a significant drawback is that the large amount of space required by the applicator beam 120 during pivoting of the beam between the operating position and the service position, i.e. the opened position. In FIG. A1, the dashed lines illustrate the service position of the applicator beam of the second press roll 114, as denoted with reference numeral 120'. For servicing the applicator beam 120, a tending bridge 130 is provided on the machine. A service operator 132 standing on the bridge 132 can carry out the necessary operations on the applicator beam 120. As shown in FIG. A1, when the applicator beam 120 is in the operating position, there is a considerably large distance between the tending bridge 130 and the applicator beam 120. For this reason, the tending bridge 130 is provided with a handrail 131 so that the service operator 132 could not even accidentally fall into the space between the tending bridge 130 and the applicator beam 120.
It is necessary to allow the space between the applicator beam 120 and the tending bridge 130 to remain quite large, because when the applicator beam 120 is pivoted to the service position 120' around the articulated joint 121, the applicator beam 120 is shifted much closer to the tending bridge 130. During the pivoting operation, the applicator beam 120 and the tending bridge 130 form a "closing nip". Therefore, on account of the desired level of working safety with regard to the applicator beam 120 during the pivoting operation and also in the service position, and with regard to the tending bridge 130, a safety clearance b must be allowed, which is at the minimum in the range of about 120 mm. By providing the safety clearance b, it is possible to avoid the risk of squeezing (of the operator) when the applicator beam 120 is being opened. Therefore, it is necessary to dimension the distance between the applicator beam 120 and the tending bridge 130 excessively large in view of the user, i.e. the service operator 132. As a result, access to the actuating members of the applicator beam 120 from the tending bridge 130 is not easy and in fact is quite cumbersome.